How can you search for a specific string within a file in the Linux operating system?

To search for a specific string within a file in Linux, the grep command is usually used.

Example:

grep "search_string" filename

This will output all lines from the file that contain "search_string".

To search recursively in all files within a directory:

grep -r "search_string" /path/to/directory

Useful options include:

• -i — ignore case
• -n — show line number
• -v — show lines that do not contain the search string

Thus, grep is a simple yet powerful tool for searching text within files.